Pneumatically powered hydraulic pump



Aug. 10, 1954 J. A. ROBERTS ET AL PNEUMATICALLY POWERED HYDRAULIC PUMPOriginal Filed April 7, 1948 5 Sheets-Sheet 1 NW JAIININ z 5 nEM m Ycan. E m m; m E mflmm flm Jan A a M Z 09.

Aug. 10, 1954 J. A. ROBERTS ETAL PNEUMATICALLY POWERED HYDRAULIC PUMPOriginal Filed April 7, 1948 Aug. 10, 1954 J. A. ROBERTS ET AL 2,685,865

PNEUMATICALLY POWERED HYDRAULIC PUMP Original Filed April 7, 1948 5Sheets-Sheet 4 TJE'IE.

1 400 99 96 94 82 INVENTORS mm-s 4. A7085? rs HOWARD F/sc/m? MAACEZ R Oi/46M ATTORN EY Aug. 10, 1954 J. A. ROBERTS ETAL 2,685,865

PNEUMATICALLY POWERED HYDRAULIC PUMP Original Filed April 7, 1948 5Sheets-Sheet 5 'Tic l. 457 24 A A VIIIIIIIIIIIIIIIIIIIIIA\\\\(VIII/1111111711174 72 47 421a Tic l, r 1 442 1 .1 5) 171a T C 7 406 BYy ATTORNEY Patented Aug. 10, 1954 PNEUI-(IATICALLY PO WERE!) HYDRAULICMP James A. Roberts, Howard B. Fischer, and Marcel: P. DHaem, Detroit,Mich, assignors to Chicago Pneumatic Tool Company, New York, N. Y., acorporation of New Jersey Original application April 7, 1948, Serial No.19,478, now Patent No. 2,588,164, dated March 4, I952. Divided and thisapplication October 16, 1951,. Serial No. 252,762

Claims. 1.

This invention relates to pumps and more particularly to pumps whichcomprise a pneumatic and hydraulic combination.

This application is a division of our original application Serial No.19,478, filed April 7, 1948, which issued as Patent No. 2,588,164, onMarch 4, 1952.

In the smaller type industrial shops and especiallyinservice garages formotor vehicles, it is often required to have a high-pressure hydraulicsource for such tools as power presses, rams, body and frame jacks,cylinder liner removers, as well as other hydraulic service tools. It isusual for such shops and garages to maintain a live air line for variouspurposes, and the present pump has been adapted to operate with theusual pressure carried by such an air line. With an air line pressure of90 pounds per square inch gauge, the pump will deliver a hydraulicpressure of 8,309. pounds per square inch gauge. It is a feature of theinvention that the control means are extremely versatile in that thehydraulic pressure delivered can be automatically maintained or releasedafter pump operation has stopped.

The prime object of this invention is to provide a new and novel pumpwhich will furnish a high pressure hydraulic delivery when connected toa low pressure pneumatic source.

Another object of this invention is toprovide a pump. which is simple toinstall and operate, has a variety of applications, has a versatilecontrol arrangement, and is reliable under all service demands.

A further object of this invention is. to-provide a pump which has lowinitial and maintenance costs, is. structurally compact, and of.relative small size and low weight.

ihese and further objects and features of the invention will become moreapparent when viewed in the light of the following specification and theaccompanying drawings wherein:

Fig. 1 is a perspective View of a pump embodying the invention;

Fig. 2 is an enlarged side elevation view of the pump;

Fig. 3 is an. end view of the pump as seen from the throttle or back endin Fig. 2;

Fig. 4 is a further enlarged longitudinal section of said pump, asindicated by the lines 4-4 in Figs. 9 audio, with the parts innon-operative position;

Fig. 5 is a fragmentary longitudinal section, as indicated by the line5-5 in. Fig. 41, showing the oil reservoir bagmaintained in spacedrelation from. its housing;

Fig. 6 is an elevation view of a pressure regulator valve used in thepump, the figure being double size as compared with Fig. 4;

Fig. 7 is a longitudinal section taken along the line l'iin Fig. 6;

Fig. 8 is a cross-section as indicated by line 8-8 of Fig. l, but on asmaller scale, showing the oil reservoir bag inflated in full lines andpartly collapsed in broken lines;

9 is a cross-sectional view of the pump as indicated by the irregularline 99 in Fig. 4, showing particularly the valves controlling thesupply of live air to the cylinder;

Fig. 10 is a cross-sectional View of the pump as indicated along theirregular line ill-iii in Fig. 4, showing the inlet check valve,discharge check valve and pressure release valve in the hydraulicsystem;

Figs. 11, 12 and 13 are diagrammatic views of the pump showingrespectively the relative positionof the various parts during an earlystage of the power stroke, return stroke, and just after maximumpressure has been reached;

Fig. 14 is a longitudinal section, looking downward as indicated by thearrows it in Fig. 4, showing the parts just prior to the attainment ofmaximum pressure;

Fig. 15 is a fragmentary cross-sectional view in the same plane as Fig.9 but on double scale and showing the pressure regulator valve anddistributor valve shifted, in response to the attainment of maximumpressure, to automatically out oli the supply or" live air to thecylinder;

Fig. 16 is a cross-section through the oilvalve block, similar to Fig.lObut with a modified pressure relief'valve of the manual or screwtype;and

Fig. 17 is an elevational view of the screw type valve used in Fig. 16.

The pump is shown in Fig. l in operating position, it being understood,as will later appear evident, that the pump can be readily controlled byfoot or hand, and will operate satisfactorily in any position withregard to the relation of the pump axis to the horizontal plane, anyparticular operating set-upbeing in accordance with the greatestconvenience thereby afforded. The pneumatic and hydraulic portions areindicated generally therein by the respective numerals 20 and 2! (Figs.1, 2 and 4). An air supply line or hose 22 is connected to the pneumaticportion 26 while a high-pressure hydraulic delivery line or hose 23 isconnected at one end to the hydraulic portion 2|, the other end. of thehose 23 being connected to a hydraulically powered tool, such as a ram,not shown. The supply and delivery hoses 22 and 23 respectively arepreferably of the ilexible type to facilitate portage of the pump, aswill be appreciated. The pump is designed to deliver a maximum hydraulicpressure of approximately 8,000 pounds per square inch gauge, when usinga 90 pound per square inch gauge air supply. However, intermediatehydraulic pressures can be obtained, if desired, by proper throttlecontrol, as will later be seen.

In constructing the pump advantage has been taken of all knownmechanical expedients to insure a maximum of efiiciency in itsoperation. In the specification, no specific mention is made ordinarilyof elements such as piston rings or seals, gaskets, and the like, but itshould be understood that these elements are provided in the pumpwherever necessary.

Pneumatic systemlive air sup ly Considering first the structure of thepneumatic portion and referring to Figs. 2, 3, 4, 6, '7 and 9, thenumeral 24 indicates a cylinder, being most conveniently in the form ofa casting, which is arranged to house and support the various elementsrequired for the operation of the pneumatic cycle. The air hose 22 isconnected to a standard inch pipe connection 25 which is screwed to therear end wall of the cylinder 24, the connection 25 being provided withan air strainer 26 (Fig. l) which is arranged to partially extend into acavity 2?, formed in the cylinder end wall. An air passageway 28 in thecylinder 24, leads upwards from the cavity 2?? and into a throttlechamber 29 which is located at the top of the cylinder 24.

The throttle chamber 29 is cylindrical in form and has an axis which isgenerally parallel to the axis of the pump proper. One end of thethrottle chamber 29 is sealed by means of a standard inch pipe plug 30,while at the opposite end, a bushing Si is press-fitted into the chamberfor a distance of a little less than onehalf the overall length of thechamber.

A throttle valve 32 is slidably fitted in part within the bushing 35,the forward portion of the throttle valve having a collar 33, whichoperatively serves to force a sealing ring 34 against a seat 35 formedon the inner or front end of the bushing 3i. Forwardly of the collar 33,the valve has a pilot portion 36 which serves to position a compressionspring 3? located within the throttle chamber 29, and interposed betweencollar 33 and a pipe plug 39 which closes the front end or" throttlechamber 29. The rear portion of the throttle valve 32 projects in partbeyond the bushing 3!, the rear extremity of the valve being in contactat all times with a throttle lever 38, which is generally L-shaped, oneleg of which is bifurcated and pivotally connected to the cylinder 24 bymeans of a pin 39, the other leg of the lever 33 extending in adirection over the throttle chamber 29 as shown. The throttle valve 32has a reduced diameter midportion, which is of such length as to uncoverports ll! and M (Figs. 4, 9 and 15), within the bushing 3i, during allpositions of the throttle valve. An exhaust port l?! extends through thebushing 3i and cylinder 24, and is so positioned that it is uncovered bythe reduced diameter midportion of the throttle valve 32, when saidvalve is in non-operative position, and is covered by the rear portionof the throttle valve, when said valve is in full operative position. Anoil hole 43, extending through the cylinder 24 and bushing 3!, isprovided for the convenient lubrication of the throttle valve 32.

It will now appear obvious that the throttling arrangement is such thatwhen throttle lever 38 is fully depressed the throttle valve 32 will beforced to a forward or full operative position, thereby covering exhaustport d2, unseating the ring further compressing the spring El, and thusallowing air in the throttle chamber 29 to pass around the reduceddiameter mid-portion of the throttle valve, and enter simultaneouslyports A l and H When the throttle lever 38 is released, spring 3!(assisted by the pressure of the live air) will force the throttle valve32 to a backward or non-operative position, thereby seating the ring 34to restrict further air passage from the throttle chamber 29, and willsimultaneously uncover exhaust port 2 to allow exit to the atmosphere ofair in passageways leading from ports 48 and 4|.

The port 4t opens into an air passageway 44 (Figs. 9 and 15) in thecylinder 24, said passageway extending forward to another section of thepump, the detailed description and function of which will be discussedlater in the specification. The port ll opens into an air passageway (15(Figs. 4, 9 and 15) which passes downwardly in the cylinder and into acircumferential recess it formed on the outer surface of a valve bushing4?.

The valve bushing 41, which is best illustrated in Fig. 15, iscylindrical in form and is pressfitted within a transverse bore in thebody or" the cylinder 24, in the manner shown. The valve bushing ll isopen from end to end and has two smooth finished bores, a larger bore#13 and a smaller bore 49 which. is concentric with and adjacent to bore48. Both ends of the valve bushing ll are internally threaded, thethreads concentric with and adjacent to the larger bore 48 being adaptedto receive a distributor valve stop 50, while the threads at theopposite end of the valve bushing are concentric with the smaller bore49 and are adapted to receive a pressure regulator valve cap 5!.

Distributor valve Reciprocally positioned within the larger bore 48 is adistributor valve 52, which has a reduced external diameter mid-portionand is internally provided with a counterbore 53 and bore 56, both ofwhich are smooth finished. Within the larger bore 53 of the distributorvalve 52, is positioned a pressure regulator valve push pin 55, whichhas a narrow integral collar 5%, slidably fitted to the bore 53. Alsopositioned in bore 53 is a distributor valve spring El which ismaintained under compression, and which surrounds a major portion of thepush pin 55. and is interposed between collar 56 and the bottom of thecounterbore in the distributor valve 52. Beyond collar 56, the pin 55has a pilot 58 for the positioning of a pressure regulator valve spring59, maintained under compression and interposed between the collar 56and a shoulder $9 in a bore H of the distributor valve stop 59. A hole62 within the valve stop 53 is provided for open communication of thebore 6! with the atmos phere. The push pin 55 has a reduced diameter, atthe end opposite the collar 55, which is arranged to slidablyreciprocate within the bore 5% of the distributor valve '52. A shoulder53 formed on the push pin 55 limits movement of the push pin on onedirection.

Pressure regulator value A pressure regulator valve 64 has a stemportion of cylindrical form reciprocably arranged in part within thebore 49 of the valve bushing 41 and projecting into a cavity 65 formedin the valve cap the diameter of said cavity being somewhat greater thanthe diameter of the adjacent portion of the valve 64. lhe opposite endof valve 64 abuts against distributor valve 52. lhe regulator valve 64,best seen in Figs. 6 and 7, has a shoulder 85 (engageable with bushing47 to limit travel of the valve in one direction), and a circumferentialgroove El which connects at two points with a zig-zag hole arrangement 8within the valve 64, the function of said groove 6'? and holearrangement 68 being discussed in theoperation of the pump as foundlater in the specification.

The distributor valve 52 and regulator valve 64 are shown in Fig. 9 in anon-operative position. In such position a plurality of ports 69,radially positioned in the distributor valve bushing 4! allow for thepassage of live air from the circumferential recess 46 to the bore 48 ofthe valve bushing 41, around the reduced diameter midportion of thedistributor valve 52, through a plurality ofradially arranged ports illin the valve bushing 41, into a circumferential recess ll formed on theouter surface of the valve bushing ll, and finally into an airpassageway 12 which extends downwardly in the cylinder 24. However, whenthe distributor valve 52 and regulator valve 64 are shifted in the valvebushing ll to the extreme left or operative position, i. e. when thedistributor valve 52 is abutting the valve stop 59, as shown in Fig. 15,ports 69 are covered by the distributor valve 52, and a plurality ofports 73 in the valve bushing 4! are placed in communication with thereduced diameter mid-portion of the distributor valve 52 as shown. Thusin the operative (Fig. 15) position, any air under pressure inpassageway l2 will pass through recess 1! and ports 10, around thereduced diameter mid-portion of the distributor valve 52, through ports13, around a reduced diameter end portion of the valve bushing 41, andout to the atmosphere. It is to be noted that a plurality of ports 14radially disposed within the valve bushing 41, are uncovered by thedistributor valve 52 when in operative position, the reason for whichwill be discussed in the operation of the pump, as found later in thespecification. Summarizing, the distributor valve 52 normally connectsthe passageway '12 to live air, as shown in Fig. 9, until displaced bythe pressure regulator valve 64, after which it connects passageway 12to exhaust, as shown in Fig. 15.

Shift valve The air passageway 12 exists into a shift valve chamber 15(Figs. 4 and 9) which contains a shift valve 76 and a shift valve springll maintained under compression. One end of the spring ll abuts againsta pipe 18, which closes the outer end of chamber '35, while the oppositeends abuts against a shoulder on the shift valve 16. The shift valve 16has an elongated projection which is snugly fitted for reciprocation ina shift valve bushingv '59, which is press-fitted within the cylinder 24at the inner end of the shift valve chamber i5. Forwardly of theshoulder of shift valve is is a conical surface which at times seatsagainst the end of the shift valve bushing E9. The shift valve bushing'59 has a rearwardly open counterbore which is somewhat larger than thediameter of the shift valve elongated projection. An air passageway 80opens into the counterbore, the function of said passageway beingdiscussed shortly. The elongated projection of the shift valve 16projects beyond the end of the shift valve bushing 19 into a main airchamber 8! in the cylinder 24, and is in contact with a piston 82 duringthe pump non-operative position, and also during a part of the movementof the piston 32. It can be seen that when the pump is in non-operativeposition, and while the shift valve 16 remains unseated by contact withthe piston 82, egress of air from the shift valve chamber is takes placealong two paths, the first of which is a continuation of the passageway12 and which passes downwardly in the cylinder 24, the other path beingaround the elongated projection of the shift valve 16, within thecounterbore of the shift valve bushing 19, and then through thepassageway 80. When the pump is in operative position, movement of thepiston 82 permits seating of the shift valve 16, due to the action ofthe spring 11, cutting off flow of air through the passageway 80, butallowing for the fiow of air through pasageway 72.

Automatic valve Passageway 12 leads into a circumferential recess 83(Fig. 9) formed on the exterior surface of an automatic valve bushing8%, which is press-fitted to a cylindrical transverse bore in thecylinder 24, as shown. A plurality of radially disposed ports 85,connect the recess 83 to the bore of the valve bushing 84, whilereciprocally arranged and snugly fitted within the valve bushing is anautomatic valve 85. Each end of the transverse bore for the valvebushing 8 has a threaded portion which is adapted to receive a valvebushing cap 81, each valve bushing cap having a cavity which isconcentric with the automatic valve 86, and which has a diametersomewhat larger than the maximum diameter of the automatic valve 86. Theautomatic valve 86 has two reduced diameter portions and 89, portion 88being of greater length than portion 89, whereas portion d9 has one endof a hole arrangement which provides an air passageway between portion89 and the right extremity of the automatic valve 26, as seen in Fig. 9.

When the automatic valve 86 is in the extreme left or non-operativeposition, two discrete circuits for air flow are established. In thefirst of the two circuits, the air in passageway 12 finds principal exitthrough circumferential recess 83 and ports 35, around reduced diameterportion 89, and through the holes 90 of the automatic valve 86, thenthrough a passageway 9i (Figs. 4, 9 and 14) in the cylinder 24, andforward to cylinder port 92 in front of piston 22, then out to theatmosphere through ports 93, which are best seen in Figs. 2 and 14. Someof the air in the above described circuit also finds egress through asmall vent 94 which is formed in the back wall of the cylinder 24, saidvent being approximately in line with the passageway 9I. It is to benoted that the passageway 9i has a second port 95 which opens into themain air chamber 8|, said port 95 being covered by the peripheral wallof the piston 82 during a major portion of the stroke of the piston. Thefunction of port 95 will be further discussed in the description of thepump operation which follows in the specification.

In the second of the two circuits, any air in the main air chamber 8|finds exit through a passageway 96 (Figs. 9 and 14) which connects themain air chamber to the bore of the valve bushing 84, around the reducedmid-portion 88 of the automatic valve 86, through a plurality ofradially disposed ports 97 in the valve bushing as, to a circumferentialrecess 98 on the outer surface of the valve bushing 84, then on to theatmosphere through a series of ports 99 formed in the rear wall of thecylinder 24, the ports 99 best seen in Fig. 3. A small vent I (Figs. 3and 9) connects the cavity in the left bushing cap 87 with theatmosphere, the purpose of which will be discussed in the operation ofthe pump, as found later in the specification.

A final detail in the structure of the pneumatic portion 23 of the pumpconcerns a short air passageway iill (Figs. 4 and 15) which connects themain air chamber BI and the cavity 65 of the regulator valve cap i, thefunction of the passageway I Ill being discussed later in thespecification.

Hydraulic system Considering now the structure of the hydraulic portion2I and referring to Figs. 2, 4, 5, 8, and 10, the numeral I02 indicatesa reservoir for housing an oil reservoir bag I93, which is made of aflexible material preferably a synthetic rubber, such as neoprene. Theoil reservoir bag I03 contains oil and completely fills the reservoirIt; when the pump is in non-operative position, with the exception of alongitudinal region on the inside of the reservoir I02, wherein a flatflexible strip Hid (Figs. 4 and 5) keeps the bag I93 away from the innerwall of the reservoir for the entire length of the strip N14. The stripI04 is riveted at one end to the wall of the reservoir H32 and is soarranged that the air passageway 64 exists into the space formed betweenthe strip and the inner wall of the reservoir. In this manner thecompressed air emerging from passageway M during pump operation, willact along the entire length of the oil reservoir bag I03 and thus avoiduneven collapse of the bag under pressure. In Fig. 8 the dashed linesrepresent a showing of a partially collapsed position of the oil bagI63.

The reservoir I02 is securely attached to an oil valve block I95 (Fig.4) by means of four screws use (Figs. 2 and 11) which pass through theblock IE5 and are arranged to also securely attach the cylinder 24 byflange means thereon, to the opposite side of the block IE5. The airpassageway 44 is arranged to pass through the oil valve block I85 sothat an unrestricted path is provided for the flow of air between thoseportions of the passageway M in the cylinder 24 and in the reservoir I92respectively. The open end of the oil reservoir bag I93 is wedgedbetween a tapered pilot iii! on the oil valve block I05 and a matchedtapered surface on the inner end of the reservoir H325, so that a liquidtight sea1 is thereby effected.

Hydraulic pressure release In the preferred embodiment the pump is sodesigned that the hydraulic pressure developed can be releasedsimultaneously with release of the throttle lever as, by an automaticpressure release valve; or if desired, by a manipulative memher afterthe throttle valve has been released, in case the operator decides tolock the automatic pressure release valve in closed position.

The numeral Hi8 indicates an automatic pressure release valve cylinderblock which is securely attached to the top of the oil valve block I05by means of two screws I09 (Fig. An oil filler hole IIII, passesdownwardly through the valve cylinder block I08 and continues into theoil valve block. I05. A pipe plug I I I is screwed into the entrance tothe oil filler hole I Ii] in the valve cylinder block Hill. A threadedportion I I2 is arranged at the mouth of the oil filler hole IIiI in theoil valve block I65, to receive the plug III in the event that theautomatic pressure release valve means is to be substituted by a screwtype pressure release means, hereinafter described in connection withthe modification of Fig. 16. An oil passageway H3 in the oil valve blockm5, connects the oil filler hole IIII with the open end of the oilreservoir bag I03, as shown in Figs. 10 and 14.

An automatic pressure release valve piston I I I is positioned forreciprocal movement within the valve cylinder block me. On the upperside of the piston H4 is formed a chamber IIE (Figs. 4 and 10), which isconnected to the oil filler hole lit! by means of an oil passageway H6sloping downwardly in the valve cylinder block from the upper region ofthe chamber H5. It will be apparent that with such an oil passagewayarrangement, the pneumatic pressure exerted on the oil in the oilreservoir bag I63 forces oil up into the chamber I I5, and the unithydraulic pressure attained by the oil in the bag IE3, is transmitted tothe upper surface of the piston lI I. Proiectable within the chamber II5 is a pressure release valve block screw Ill, which can be rotated bymeans of a handle II8, for engagement with the piston I i i, in theevent that the operator desires to prevent the automatic opening of therelease valve.

On the under side of the piston I It is a pressure release valve springII9 (Figs. l and 10) maintained under compression at all times, andwhich is in abutting relationship with the under side of the piston I I4through the intermediary of a washer I26, the opposite end of the springbeing in abutment with the top surface of the oil valve block m5.concentrically positioned beneath the piston II is a pressure releasevalve IZI, having the form of a cylindrical plunger, and which isadapted for reciprocal movement within a smooth finished bore I22extending downwardly in the oil block I55. The lower portion of therelease valve I2I has a reduced diameter which terminates in a conicalpoint. At the lower end of the bore H2, and surrounding a major portionof the reduced diameter of the release valve I2I, is a. threaded portionI23 which is adapted to function in the event that the screw typepressure release valve is substituted as shown in Fig.

At the bottom of the bore I22, and concentrically arranged with the axisof the bore I22 and release valve IZI respectively, is a small oilpassageway I24 (Figs. 4, l0 and 14) which extends downwardly within theoil valve block I65 and connects with a larger diameter longitudinal oilpassageway I25. Another longitudinal oil passageway I26 connects thethreaded portion I23 of the bore 622 to the open end of the oilreservoir bag Hi3, as illustrated in Figs. l and 10.

When the conical point of the pressure release valve I2I is seated inthe opening of the passageway IZA, the flow of oil from passageway I25through passageway I2 3, about the reduced diameter portion of the valveI2 I, through the passageway I25, to the oil reservoir bag IE3, isprevented; and conversely, when the pressure release valve is unseated,the now of oil through said between the high and low pressure ports ofthe hydraulic system for a purpose hereinafter set forth.

Hydraulic pumping circuit A short vertical oil passageway I21 (Fig.connects the longitudinal passageway H3 to a chamber I25 formed in abushing I25, which is positioned above a first check valve I33 (Figs. 10and 14). The check valve I36 is adapted for reciprocable movement withina smooth finished vertical bore I3I formed in the oil valve block I65,the lower end of said bore opening on the bottom surface of the blockI65. The check valve lie is tubular in form, the top end being closedand having a beveled edge enga eable with a valve seat on the lower endof bushing I 26 which functions to close the bottom of chamber I26.Within the check valve I36 and extending therefrom, is a compressionspring I32 which abuts against an internal shoulder in the check valveI3II at the upper end, and a check valve spring spacer I33 at the lowerend. The spring spacer I33 is smoothly fitted to the bore I3I and ispositionally maintained therein by means of a pipe plug I34, which isthreadably affixed at the lower end of said bore I3 I. At the upper endof the check valve I35 is a plurality of ports I35 which are radiallydisposed in the Wall of the check valve, the outside diameter of thecheck valve I 30 at the region'of the ports I 35 being somewhat lessthan the outside diameter of the lower portion of the check valve.Entering into the check valve bore I3I, and adjacent the bottom edge ofthe bushing I23, is a transverse oil passageway I36.

Check valve I36 functions as an inlet valve for the pump. It Will beapparent that the operation of check valve I36 is mainly dependent uponthe relative pressure of the oil in chamber I28 and passageway I 35.When the pressure of the oil in chamber I28 acting against the top ofthe closed end of the check valve I39, is greater than. the combinedpressure of the oil in passageway I35 and the compressive pressure ofthe spring I32 acting on the bottom of the closed end of check valveI36, the check valve will be unseated, and oil will flow from thechamber I23, around the reduced diameter portion of check valve I36, tothe passageway I36. Conversely, when the pressure of the oil in chamberI 28 is less than the combined pressure of the oil in passageway I 55and the compressive pressure of the spring I32. the check valve will beseated and there will be no iiowof oil between the chamber I25 and thepassageway I 35.

The passageway I35 leads through an oil pressurizing chamber I37 (Figs.10 and 14), which is cylindrical in form and which is concentricallyarranged about the longitudinal axis of the pump, thence to a shortpassageway I38 which exits into a chamber I39 formed in a bushing I 55,which is positioned above a second check valve or discharge valve MI.Check valve MI is structurally like the check valve I 36, and isreciprocably fitted to a smooth finished vertical bore I 52 formed inthe oil valve block I IE5. The lower end of the bore I 42 opens into thebottom surface of the block m5 and is adapted to receive a pipe plug I43, by means of a threaded portion at the end of the bore. A compressionspring I44, arranged within and extending from the check valve I4I,abuts against a shoulder therein at one end, and pipe plug its at theother end, thereby serving to seat the check valve I4I at the lowerinner edge of the bushing I46. An opening I45 (Fig.

4) in block I05, connects the check valve vertical bore I42 at theregion adjacent the bushing I46 with the longitudinal oil passagewayI25. The passageway I25 is also connected at the region of the openingM5, to a cavity I46 (Figs. 4, 10 and 14) formed in the side of the oilvalve block I65, said cavity having a threaded portion adapted toreceive an L It'd (Figs. 2, 10 and 14), to which is threadably connectedthe hydraulic delivery hose 23.

It will be apparent that when the pressure of the oil acting on theclosed end of check valve I II within chamber I39, is greater than thecombined pressure of the spring I44 and the pressure of the oil inpassageway I25 acting on the'under side of said closed end, the checkvalve MI will be unseated and oil will flow from chamber I 39, aroundthe reduced diameter of the check valve I iI, though opening I45, intopassageway I25, to cavity I 45 and on to the hydraulically powered tool(not shown) connected to the remote extremity of the hose 23.Conversely, when the oil pressure acting on the closed end of the checkvalve I4I within the chamber -I as is less than the combined pressure ofthe spring we and the pressure of the oil in passageway I25, the checkvalve I4! will be seated and there will be no flow of oil between thechamber I39 and the hose 23. Thus, the periodic lowering and raising ofpressure in the oil pressurizing chamber I 37 alternately draws oil fromthe reservoir bag I66, past the inlet check valve I33 into thepressurizing chamber; and then forces the oil, out of said chamber pastthe discharge check valve I II to the delivery hose 23.

Pump apparatus On the side of the oil valve block I opposite the oilreservoir I62, is an elongated projection I48 (Figs. 4 and 14) which isconcentrically arranged with respect the axis of the cylinder .24. Theprojection I48 has a counterbore I49 which extends the entire length ofsaid projection and continues into the oil valve block I55 for a shortdistance, where it meets with a bore which forms the pressure chamberI31. Since the diameter of the counterbore I46 is larger than thediameter of the bore forming the pressurizing chamber I31, a shoulder I56 is formed at the junction of the two bores, as seen in Figs. 4 and14. A piston ram bushing I5I is snugly fitted to the counterbore I49,one end of the bushing I5I abutting against the shoulder I50, the otherend of said bushing being in abutment with a bushing nut I52, which isscrewed into a threaded portion at the rear end of the counterbore I49,as shown. The bushing I5I has a bore which is smooth finished forreciprocable movement therein of a piston ram I53. A. circumferentialrecess I54, formed in the bore of the bushing I5 I surrounds the pistonrain I53 and is arranged to connect with a passageway I 55, which passesthrough the bushing I5I and the oil valve block I55, and exits into theopen end of the oil reservoir bag I33. In this manner any oil whichleaks by the piston ram I53 during pump operation, finds ready passageback to the oil reservoir proper.

The piston ram I53 has a head portion I56, which is maintained inabutting relationship with the piston 82 by means of a compression sprinI57, through the intermediary or" a piston ram washer I58. the oppositeend of the spring I5? abutting against the wall of the oil valve block Iaround the base of the projection I48. The strength of spring I5! issumo-lent to fully retract the piston t2 when the air in the main airchamber $5 is exhausted to the atmosphere.

The length of the piston ram E53 is such that when the piston 32 is innon-operative position, the end of the ram within the oil valve blockIE5 is approximately in line with the shoulder I5il, as shown in Fig. l.The diameter of the piston ram I53 is approximately two-thirds thediameter of the pressurizing chamber I31. The forward end of thepressurizing chamber I3! is closed by a pipe plug I59 which provides aliquid tight seal for that end of the pressurizing chamber I31.

On the side of the piston 82 within the main air chamber 3i is acylindrical projection {60 arranged concentrically with the pump axis,said projection I56 serving to limit the extreme back ward movement ofpiston 82, as is clearly evident in Fig. 4. A piston ram seal I 6i madeof a flexible material such as leather for example, surrounds theprojection I and slidingly engages the walls of the cylinder 24, servingto provide a sealing means for the air in the main air chamher 8 I. Theseal i6! is positionally maintained by means of a washer I62 and aretaining ring I63, which is fitted to the projection I50, as shown.

Opemtion Before entering into a description of the op eration of thepump, it is desired. to point out certain features or expedients whichare embodied in the structure of the pump, some of which may not haveappeared obvious.

First, the length of the pressurizing chamber I 3! is such that the endof the piston ram 553 is free from contact with the closed end of saidpressurizing chamber, 1. e. the plug I55, when the piston 82 has movedto the extreme limit of its working stroke.

Second, the quantity of oil in the pump hydraulic system at thecompletion of an operating cycle i. e., after the oil has returned tothe reservoir, is the same as the quantity of oil in the pump hydraulicsystem before the start of an operating cycle, excepting of course, thatwhich may be lost due to any leakage. This is arranged by the use of acheck valve hose coupling, not shown, of the type having a spring seatedvalve which is unseated or opened only when the coupling is connected.The male portion of the coupling is attached to the end of the hydraulichose 23, while the female portion is attached to the hydraulicallyoperated tool. Thus when the coupling is connected, the pump forces oilfrom the hose 23 past the open check valve hose coupling and into thehydraulically operated tool connected thereto, whereas the return strokemovement of the hydraulically operated tool forces the oil past thecheck valve hose coupling into the hose :3 and back to the pumpreservoir proper. The use of a check valve hose coupling of such type,provides for ready make-and-brealr connection of the pump to whatevertype of hydraulically operated tool it is desired to use at the time,and still prevents the oil from draining from the hose 23 when the hoseis not attached to a tool.

Third, regarding the capacity or output of the pump, it is obvious thatsuch is merely a matter of proportion of the various pump parts.However, for a commercial embodiment of this invention, an oil deliveryflow of 38 cubic inches per minute at 8,000 pounds per square inch isattained from an oil reservoir capacity of 45 cubic inches. To augmentthe oil capacity of a pump of any given size, the use of an auxiliaryreservoir as later described and illustrated in the drawings, may beprovided.

Fourth, it is to be noted that the pump is supported for normal uprightposition by means of flat portions on the bottom of the cylinder 25, oilvalve block Hi5 and oil reservoir It I, as best seen in Fig. 2. However,as has been mentioned heretofore, the pump will operate satisfactorilywhile maintained in any desired position.

Finally, in accordance with the usual construction of machines in thisgeneral class, an air line oiler of any suitable type may be provided inorder that a small amount of oil may be introduced into the live air asa lubricant for the valves and the air operated piston.

Turning now to a consideration of the operating cycle of the pump, l, 9and 10 illustrate the relative position of the various movable parts ofthe pump when the pump is in non-operative position. Since the foregoingdescription of the pumps structure has been made with referenceparticularly to the pump in non-operative position, it is not deemednecessary to again discuss the relative position of the movable parts ofthe pump when in non-operative position. If the operator desires thatthe hydraulic pressure de veloped by the pump and delivered to thehydraulically operated tool, is to be automatically released aiter thethrottle lever 38 is released, he merely observes that the handle H8(Fig. 4) has been rotated so that the release valve screw II? is freefrom contact with the release valve piston H4; whereas, if he wishes thedeveloped hydraulic pressure to be maintained after the throttle leveris released, he checks to see that the handle i I8 is rotated so thatthe release valve screw II? is in-contact with the piston II l.

Assuming then that the pump is connected to a source of live air bymeans of the air hose 22, and the delivery hose 23 is connected to ahydraulically operated tool, and that the automatic release valve is setfor automatic release (as in Fig. 4), the operator initiates the pumpoperating cycle by fully depressing the throttle lever 38. The throttlevalve 32 is thereby unseated and live air flows from the throttle valvechamber 29, past the valve seat 35, about the reduced diameter of thethrottle valve 32 and into ports 40 and M. The air entering port 49passes through the air passageway td, enters the air reservoir Hi2 andacts upon the exterior of the oil bag m3, thereby pressurizing the oilcontained therein and forcing oil into the oil passageway H3, from whichit passes into oil passageways I Hi and I2! (Fig. 10). The oil inpassageway I I6 flows upward into the chamber 5 I5, and acts upon thepiston I I4, which results in the seating of the pressure release valveiZi in the opening of the passageway I24. The oil in passageway I21enters the chamber I28, where the pressure of said oil unseats the inletcheck valve fist, the oil thereby advancing through passageway I355 intothe pressurizing chamber I31, wherein it is eventually pressurized bythe advance of the piston ram I53.

The air going through port ti (Fig. 9) passes through passageway 45 andports 69 into the bore of the valve bushing 41, about the reduceddiameter mid-portion of the distributor valve 52, and through the radialports 79 and annular recess II to the air passageway F2. The air frompassageway T2 enters the shift valve chamber l5 (Fig. 4) some of the airpassing onward through said chamber and into the continuation of passageway 12, while some fiows past the unseated shift valve 16 into thepassageway '86. The air in passageway 80 enters the cavity in the leftcap 8! (Fig. 9), thereby shifting the automatic valve -85 to the right,where the end of the valve 86 abuts against the bottom of the cavityformed in the other cap 8'5. Ihe automatic valve 86 in shifting to theright, uncovers the vent tilt so that air in the cavity of the left cap37 is exhausted to the atmosphere.

The air which flows downward from the shift valve chamber 15 through thecontinuation of passageway 72 (Fig. 9), is allowed to exhaust to theatmosphere before the automatic valve 86 is shifted to the right, suchexhausting taking place by way of annular groove 83, bushing ports 85,valve recess 39, passageways 9a in the automatic valve 86 and throughthe passageway 95 (Figs. 4 and 11) port 92, and then through cylinderexhaust ports 33. After the automatic valve 36 is shifted to the right,the air from passageway l2 flows about the reduced diameter portion 85of the automatic valve 85, into passageway 95 (Figs. 9, 11 and 14) fromwhere it enters the main air chamber 8!. As the air builds up pressurein the main air chamber 3i, piston 82 begins to move, which results inthe compression of the spring l5? and the simultaneous pressurizing ofthe oil in chamber it? by means of the advance therein of the piston ramI53. As the piston continues its movement which constitutes the powerstroke, contact with the shift valve '58 is released and ended, as theshift valve i6 is allowed to seat by action of the spring ll, therebycutting off the how of air from chamber '55 to the passageway 80.

Power stroke Fig. .11 illustrates the first stage in the power stroke ofthe pum as just discussed. The singleheaded arrows indicate air at nogreater than airline pressure, the double-headed arrows indicate oilunder air line pressure, and the tripleheaded arrows indicate oil underhigher pressure asa result of the pressurizing which takes place inthepressurizing chamber 31. It is to be noted that the inlet check valve530 has been seated. while the discharge check valve i l! has beenunseated, each as a result of the pressurization oi the oil in thepressurizing chamber 53?, and that the oil is flowing under pressureinto the oil delivery hose 23. As has been indicated in the precedingdiscussion of the pumps structure, the compression springs I32 and Hitof the check valves lttl and NH respectively, provide for the automaticactuation of the said valves in accordance with the relative pressure ofthe oil in the pressurizing chamber i3! and the'oil the oil bag 1%.

It may be pointed out that the maximum pump delivery pressure or" 8,006pounds per square inch is not ordinarily realized after the completionof the first power stroke, but rather is attained only after a series ofsuccessive power strokes, in accordance with the amount of oil that willhave to be pumped to the hydraulic tool which is connected to the pump.In other words, some tools may require full oil capacity of the pumpbefore the maximum oil pressure can be built up, in which case thepiston 82 will undergo a certain number of reciprocations to pump therequired amount of oil, and hence the maximum oil pressure of 8,000pounds per square inch will be achieved only on the final power stroke.

Ordinarily, the operator keeps the throttle lever 38 fully depressedcontinuously during a succession of piston reciprocations until thedesired oil pressure is attained, after which he re leases the throttlelever 38. By opening the throttle valve only part way and by closing itwhen desired, the operator may control the movement of the ram (notshown) on the driven tool. Thus the ram may be run out at full speed orit can be inched forward, stopped, held in position, or retracted, asdesired.

Return stroke Fig. 12 illustrates the relative position of the variousparts of the pump just after completion of a power stroke and at thebeginning of the return stroke. It will be seen that when the piston 82is advanced during the power stroke to a certain position, which can betermed maximum forward position, cylinder port 35 is uncovered and port$2 is simultaneously covered by the piston head, thereby allowing air inthe main air chamber 8| to flow through port 95 into passageway 9 l tothe reduced diameter midportion 89 of the automatic valve 35, and intohole arrangement 90 within said automatic valve. The air which exitsfrom the hole arrangement Sit, builds up pressure behind the right endof automatic valve 85 within the cap ti, and forces the automatic valveto the left, i. e. the end being forced into abutment with the bottom ofthe cavity in the other cap 3?, Upon movement to the left the valve 86displaces the air in lei cap 8'5 which escapes to atmosphere around theperiphery of valve 86 and through the small port I60 (Fig. 9). The shiftof Valve 86 to the left places the passageway 55 (Figs. 9 and 12) incommunication with the ports 59 by way of the reduced diameter portion88 of the automatic valve 86, thereby exhausting the air in the main airchamber 8! to the atmosphere. As soon as the pressure in the main airchamber is released, the spring I51 acts to force the piston 82 rearwardto its initial position within the cylinder 24. It is to be noted thatthe port 95 is uncovered only for that instant during which the piston82 is in maximum forward position, and that some of the air inpassageway '52 is bled to the atmosphere during the return stroke of thepiston via the 'holearrangernent Q93, passageway 91, ports 92 and 93,and also restricted vent 94.

During the return stroke of the piston, the pressurizing chamber 13?expands in size to reduce the pressure on the oil therein, while the airin passageway M is still acting upon the oil bag Hi3, thereby forcing aslug of oil past the inlet check valve I38 and into the pressurizingchamber I31, in preparation for the next pressurizing stroke of pistonram I53.

As the piston 82 repeatedly reciprocates, the oil pressure graduallyrises in the discharge hose 23, causing a corresponding in theresistance of discharge valve Mi to opening movement and in theresistance ofiered by the oil in pressurizing chamber 3? to forwardmovement of the piston .ram E53. A ainst this increased opposition theforward motion of the piston 82 becomes lcss rapid as compared withpreceding strokes. Under ordinary operating conditions, however, theopposition is still small enough, and the forward travel of the pistonstill fast enough, to prevent the air in cylinder chamber (it fromapproaching line pressure (say p. s. i.) as the chamber expands 'on thepower stroke. Accordingly "the pressure regulator valve B l and dis- 15tributor valve 52 remain in the non-operated position of Fig. 9 undernormal operation.

Oil pressure release It has been pointed out that the piston 82 startsto reciprocate when the throttle lever 38 is depressed and continues ina succession of pumping strokes until the throttle lever is released.When this occurs, the oil pressure in hose 23 may or may not beautomatically released, depending upon the setting of the manipulativescrew ill. If the screw (Fig. 4) is forced down on pressure releasevalve piston l is, the pressure in hose 2% will be maintained becausethe oil in that hose has no means of escape bacla to the oil reservoirbag m8.

If, on the other hand, the operator desires to have the oil releasedfrom hose 23 automatically upon closing of the throttle, he firstconditions the machine for automatic pressure release by withdrawing thescrew ii? out of the path of the pressure release piston l Hi. Whenoperating with such a setting the valve piston H is held down by thepressure of oil admitted through passage Hi5, which is maintained onlyso long as live air is delivered through the throttle valve and passagefi l. When such pressure is released the pressure release valve 25 risesunder the influence of spring are to open a path from the oil hose 23direct to the reservoir bag 83, independently of the check valves, asabove described.

Manual pressure release In the modification of Fig. 16 the automaticpressure release valve piston lid, and associated housing, spring, etc,are omitted, to simplify the structure and reduce the manuiactun ingcost. Instead of the automatic valve 52 l, the modification comprises amanual valve 12in (Figs. 16, 1'7) having a threaded portion 52 lbengage-able with the screw threads 5 23 in the oil valve block m5.Seating and unseating of the modified pressure release valve lilo iseffected by turning the handle 52 lo. In other respects the valve itlais comparable to the automatic valve 52 i. In the modification of Fig.16, the threaded opening l 12 is directly engaged by a pipe plug forclosing its upper end.

Pressur regulator In the foregoing discussion it was assumed that theoperator would release the throttle lever and stop the pumping operationbefore the pressure in oil hose is attained a dangerous value. If hefails to release in time, however, the pressure regulator automaticallycomes into operation and stops the reciprocation oi the piston, withouthowever, releasing the pressure of the oil already pumped into the hose.

Figs. 13 and 1a illustrate the relative position of the various parts ofthe pump just at the time that maximum pump pressure is reached.Assuming that the maximum oil pressure of the pump under discussion is8,000 pounds per square inch, then the efiective air pressure in themain air chamber 8| will not realize a maximum value until the maximumoil pressure is realized in the pressurizing chamber I37. When thisoccurs, the piston 82 is short stroked and the air in the main airchamber 8| has time to build up and approach line pressure, and by wayof passageway llll, to force the regulator valve 6t toward the left inthe valve bushing 41, which results in the simultaneous shifting to theleft of the distributor valve 52, so that the end of said valve 52 abutsthe distributor valve stop 50, as shown in Fig. 15. In such a position,the distributor valve 52 allows exit to the atmosphere of the air in themain air chamber 8|, by way of passageway 95, about the portion 88 ofthe automatic valve 86, through passageway l2 and onward about thereduced diameter mid-portion of the distributor valve 52, and finallythrough ports 13 in the bushing 51.

When the distributor valve 52 is in its shifted position (Fig. 15) theports 89 are covered by the distributor valve, while th ports it areuncovered. This allow the live air from passageway 55 to act upon theend of the distributor valve 52 which is in abutment with the regulatorvalve $4, and to hold the distributor valve in shifted positionindependently of the pressure exerted upon the distributor valve by theregulator valve 64. Under these conditions the distributor valve 52 maybe released from shifted position, only upon release of the throttlelever 38, which results in the cutting off of air flow to passageway c5,and allows escape of air from passageway 55 to the atmosphere by meansof port 4 2, thus permitting the regulator valve spring 59 to shift thedistributor valve 52 to its first or normal position. The strength ofthe regulator valve spring 59 is a factor which determines the point ofcut-ofi for the hydraulic delivery pressure, it being obvious that aspring with a lower compression factor will allow the distributor valve52 to be shifted at a lower value of hydraulic delivery pressure, whichis directly reflected in the pressure of air in the main air chamber 81.It will be seen that the zig-zag hole arrangement 58 of the regulatorvalve 64, prevent the trapping of air Within the chamber formed, in theValve bushing t'l at the end of the distributor valve 52, and thusallows the unrestricted seating of said distributor valve.

In our parent application Serial No. 19,478, filed April 7, 19 18, whichissued as Patent No. 2,588,164, on March 4, 1952, reference is made(Col. 17, lines 51-54) to this application as being a division of theparent application, and including claims to an auxiliary reservoirsystem. Said claims, and related subject matter, have been cancelled outof this application and now form part of a divisional application SerialNo. 390,234, filed November 4, 1953.

What is claimed is:

1. In a pneumatically powered hydraulic pump, a reciprocating air motorcomprising a. cylinder, a piston therein, a throttle valve connected toa source of live air, an inlet passageway leading from the throttlevalve to an inlet port for the rear end of the cylinder, an automaticvalve interposed between the throttle valve and inlet port and arrangedin a normal position to continue the inlet passageway for admitting liveair to the rear end of the cylinder to drive the piston on its powerstroke, said automatic valve being adapted in an operated position tointerrupt the inlet passageway and cut off the supply of live air to theinlet port, means for automatically returning the piston to the rear endof the cylinder upon interruption of the supply of live air to the inletport, means for automatically moving the automatic valve from normal tooperated position upon completion of the Working stroke of the piston,thereby initiating the return stroke, a distributor valve in the inletpassageway arranged in a normal po sition to continue the passageway butin an operated position to cut oil the supply of live air to the inletport, said distributor valve being moved to operated positionautomatically upon attainment of a predetermined pressure in the rearend of the cylinder.

2. In a pneumatically powered hydraulic pump, a reciprocating motoraccording to claim 1, in which the distributor valve is shifted tooperated position by a pressure regulator valve, the latter beingunresponsive to normal pressure fluctuations in the cylinder and beingoperated upon development of a predetermined cylinder pressure resultingfrom stalling or substantially stalling of the piston on its powerstroke under normal load.

3. In a pneumatically powered hydraulic pump, a reciprocating air motoraccording to claim 2, in which the distributor valve is arranged to beheld in operated position after being shifted, the holding meanstherefor being operated by live air and being released upon closing ofthe throttle valve whereby the operation of the distributor valve iseffective to discontinue reciprocation of the piston until the operatorfirst closes then later re-opens the throttle valve.

4. A reciprocating air motor comprising a cylinder, a pistonreciprocating therein, a throttle valve connected to a source of liveair, an inlet passageway leading from the throttle valve to an inletport for the rear end of the cylinder, a plurality of valves interposedbetween the throttle valve and inlet port and arranged in the normalposition of each valve to continue the inlet passageway inadmitting'live air to the rear end of the cylinder to drive the pistonon its power stroke, each valve arranged in an operated position to cutoff said inlet passageway to interrupt the supply of live air to theinlet port, means for operating one valve upon completion of the for-Ward stroke of the piston, and means for operating the other valve uponthe attainment of a predetermined pressure in the rear end of thecylinder, and means for automatically moving the piston rearwardly upondiscontinuance of live air through the inlet port.

5. A reciprocating air motor according to claim 4, which includes meansfor holding the other valve in operated position as long as the throttlevalve is open.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,067,233 Adams July 15, 1913 1,164,134 Stansell et al Dec.14, 1915 2,001,487 Doherty May 14, 1935 2,029,240 Kuhn Jan. 28, 19362,065,144 Miller et a1 Dec. 22, 1936 2,324,701 Herman July 20, 19432,347,379 Teetor Apr. 25, 1944 2,406,747 Davis Sept. 3, 1946 2,433,759Hess Dec, 30, 1947

